Dental impression-cup.



I. A. BURNETT. I DENTAL IMPRESSION CUP. APPLICATION rum) SEPT. 28

Patented Feb. 21, 1911.-

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pin s IRA A. BURNETT, OF CHICAGO, ILLINOIS.

DENTAL IMPRESSION-CUP.

Specification of Letters Patent.

Application filed September 28, 1910.

1.0 all whom it may concern: I

Be it known that I, IRA A. BURNETT, of Chicago, in the county of Cook and State of Illinois, have invented certain new and useful Improvements in Dental Impression- Cups, of which the following is a specification.

My invention relates to dental appliances for holding the wax biscuits when taking wax impressions of the gums for use in making artificial dentures.

The objects of my invention are, first, to provide a connection for the plates in conjunction with a lever, whereby the operator can assist the force of the bite in shoving the lower plate back in the patients mouth, during the biting operation; and, second, to provide means for preventing lateral movement of the plates relatively to one another and modifying their longitudinal pose in operation. I attain these objects by the appliance constructed as illustrated in the accompanying drawings in-which Figure 1 is a top plan view of the preferred construction of the device showing my invention. Fig. 2 is a bottom view of same, the dotted lines representing a recess in a thickened portion of the upper plate. Fig. 3 is an edge view the device shown as being open. Fig. 4 is a section on the line 1 1 of Fig. 1.

Like reference numerals marked on the drawings indicate like parts throughout the several views.

The upper part comprises a tray-like plate 5, adapted to take the upper wax biscuit and terminating in a handle 6. The inner part of plate 5 is provided with an upward increase of thickness at its mid-width 7 having a recess 8 formed from the under surface of plate 5. This recess is covered at the end and for a portion of the bottom by a plate 9, which carries a spring 10 or pin that projects into said recess. The handle 6is provided with a recess or slot 11 and, at the extreme outer end, terminates preferably in a downward projection 12. The lower part comprises a tray-like plate 13, adapted to hold the lower wax biscuit for the lower jaw and provided with an inwardly-projecting lug l4. Said lug is adapted to snugly fill the recess 8 and engage the part 10 so as to hold the inner ends of the plates 5 and 13 yieldingly or lightly together and permit them to slide lengthwise, one upon the other, in operation,

and to be slightly separated at the front. The plate 13 at the outer edge terminates preferably in a narrow extension 15 provided with a slot 16 at its extreme outer end, which lies in line with the slot 11 of the handle 6. In said slot 11 is fitted, an angular lever which is pivoted at 17 to the handle 6, and comprises, preferably, athumb piece 18, a finger piece 19, and a short arm 20. Said arm 20 is pivoted in the slot 16 of the part 15, as best seen in Fig. 4:. The parts of said lever which are below said thumb piece work through and below the slot 11 of the handle, and said finger piece is provided with a stop pin 21 which, striking the under surface of the handle across the slot, limits the opening movements of the thumb piece and plates as seen in Fig. 3.

It is preferred to have the front and side margins of the plates 5 and 13 provided with flanges 22 adapted to stand outside the gums, but this is not deemed essential.

- The wax is applied to the plates on the level portions within the marginal flanges and to the front of the thickened part, as at 7. This part is thicker on the upper plate but on both the tendency is to prevent the wax from passing back toward the inner edge of the plates, and the upper surface at 7 is rounded substantially to correspond in shape with the palatine arch.

The operation of applying the wax biscuit to the plates and entering and pressing the upper wax mass in place to get the required impression of the upper jaw, or teeth is well known by those skilled in the art and it is deemed not necessary to particularly describe the same here.

The novel part of the operation consists in having the innermost ends or parts of the plates kept lightly together while permitting a sliding movement toward the front; in having the outermost part of the plate 13 tilted downward toward the front while it is being moved outward beneath the plate 5 and the thumb piece 18 is being elevated, as shown in Fig. 3; in having the plates keep their relative lateral position through the instrumentality of a lug 14: and the angular lever, respectively, working in a recess 8 and slot 11 to hold a close working lateral position of said plates at the front and rear, and

to enable the operator, by clasping the ban dle 6 and pressing down on the elevated thumb piece 18, to put additional force to that furnished by the bite of the patient for fulcrumed on the handle and having an arm pivoted to said forward extension for imparting backward and upward movement to the lower plate, as specified.

2. In a dental impression cup of the class described, the combination with an upper plate having a slotted handle, of the lower plate having forward extension beneath the handle and mounted to slide longitudinally and tilt relatively to the upper plate, and an angular lever pivoted in the slot of the handle and having an arm extending below the handle pivoted to said forward extension and an arm extending above the handle, for imparting backward and upward movement to the front of the lower plate, as specified.

3. In a dental impression cup of the class described, the combination with an upper plate having a slotted handle of a lower plate having forward extension beneath the handle and mounted to slide and tilt on the upper plate, and a lever pivoted in the slot of the handle and having an arm (20) extending below the handle pivoted to said forward extension and another arm (19) extending below the handle, for imparting forward and backward movement to the front of the lower plate, as specified.

4:. In a dental impression cup of the class described, the combination with a masterplate (5) having a handle on the outer end and a companion plate (13) having an outer extension, of connecting means at the inner ends of said plates adapted to hold them yieldingly together, and lever mechanism in connection with the handle and outer extension and adapted to impart sliding and obliquing movement to the companion plate, as specified.

IRA A. BURNETT.

IVitnesses SARA MORAN, ADALYN PINKERTON. 

